The X'4' reason code indicates that the ANSAREA you provided is too small to contain all the requested data. You can reissue the IXCMG macro using the value returned in AMDATLEN (total length of answer area needed to contain all the requested information) as the length of your answer area. However, be aware that the IXCMG information returned is a snapshot of the current environment — which might change between one invocation of IXCMG and the next. (For example, additional systems might have joined or left the sysplex, thus changing the number of system records in the answer area.) You must provide code to handle the X'4' reason code in case the length of the record(s) you are requesting ever changes.